With widespread awareness of its significant health benefits, regular exercise including progressive resistance strength training has become a matter of high priority to many members of the general public. Progressive resistance strength training is a type of strength training that uses free weights, exercise weight stack machines, compressed air (pneumatics), hydraulic resistance, elastic/rubber bands and gas springs as resistance to strengthen muscles. The key to this type of exercise is adjusting the resistance as the person progresses. A major obstacle faced by most in following a progressive resistance strength training program is the lack of readily accessible equipment that enable them to exercise different portions of the body at home. Ideally, an in-home gym facility is equipped with various exercise machines and implements for exercising different portions of the body but most do not.
The most difficult and overlooked muscles to exercise at home with progressive resistance are the muscles of the core (transverse abdominal, internal obliques, external obliques, rectus abdominis and erector spinae). These muscles are antagonistic in that they oppose the movement of one another. Proper strength and tone of each muscle group is important for proper posture, reduction of back injuries and physical health. Despite the importance of the abdominal, and lower back muscles, these muscles tend to be forgotten in most home exercise gyms. Consequently, there is a need for a core exercise machine that uses progressive resistance, is compact, portable, affordable, and easy to use.
Versatile machines that are reconfigurable to enable various exercises do exist. Those machines, however, typically include complex arrangements of mechanical parts and require complicated series of adjustments to reconfigure the machine for different exercises. Where such complexity is not present, the machines are either undesirably limiting in the number of different exercises that may be performed on them, don't allow for any significant resistance, don't offer a wide range of resistance or are physically of such substantial mass and dimensional extent that they may be fully utilized only in certain wide-open areas of a given home, and are hardly movable, let alone portable. Preferably, an in-home machine with such versatility offers a broad range of progressive resistance, is safe, easy to use, affordable, light weight, and collapsible for storage.
Known exercise machines provide weights or a reaction force as a source of resistance (weights are heavy and expensive). Rubber elements used as stretchable resistance bands have been widely used to oppose motion of certain mechanisms in an exercise machine (the problem with a stretchable band is that the resistance greatly increases as the band stretches and they tend to dry out and break). Gas springs are known as well which have a piston/cylinder arrangement. Gas inside the cylinder flows through or around the piston from one side to the other as it moves back and forth in various designs; usually the piston has one or more holes or valves in it. The whole cylinder is completely sealed, and when the piston rod is inside the cylinder, it takes up room that the gas previously occupied. In other words, when a gas spring is fully pushed in, the gas inside compresses by an amount equal to the volume of the piston rod. Furthermore, the net force on the piston is out of the cylinder because the piston rod within the cylinder takes up space and thus there is a pressure differential across the piston. For instance, a gas spring in U.S. Patent Publication No. 2005/0101464 provides a resistance force which increases somewhat during compression. Typically, Nitrogen is the working gas inside the gas spring.
Despite numerous exercise machines on the market, there remains a need for a portable machine that works the core muscles of the body, that can supply similar resistance to weights yet be safer, portable, moveable, affordable, and which can easily be adjusted for different exercises and users.